Management of type II dens fractures - A case-control study

Study Design, A case-control study of patients with isolated type II dens f ractures treated with halo vest immobilization. Objectives. To evaluate age as a risk factor for failure of halo immobiliza tion in patients with type II dens fractures. Summary of Background Data. The literature reports an average fusion rate o f approximately 70% in patients with type If dens fractures treated by halo vest immobilization. Although many investigators have examined patient age as a risk factor for nonfusion using halo immobilization, all studies have been supported only by Class Ill data. These studies, consequently, carry little or no statistical significance. Therefore, a case-control study base d on Class II data was designed to evaluate age as a risk factor for failur e of halo vest immobilization in patients with type II dens fractures. Methods. Thirty-three patients with isolated type II dens fractures treated with halo vest immobilization at the University of Iowa Hospitals and clin ics between 1983 and 1997 were included. Type II fractures were defined wit h plain radiography as per the Anderson-D'Alonzo classification. Cases were defined as nonfusions after halo immobilization, whereas control subjects represented successful bony unions attained with halo immobilization. Results. When the case and control groups were compared, there was no signi ficant difference between the groups in the presence of concomitant medical conditions, sex, the amount of fracture displacement, the direction of fra cture displacement, the length of hospital stay, or length of follow-up. Ag e more than 50 years was found to be a highly significant risk factor for f ailure of halo immobilization (P = 0.002; Fisher's exact test, two-tailed). The odds ratio of these data indicate that the risk of failure of halo imm obilization is 21 times higher in patients aged 50 years or more. Conclusions. Surgical intervention should be considered in those patients a ged 50 years or more who have a type ii dens fracture, if it can be accompl ished with acceptable risk of morbidity and death.